Agricultural combines are configured to travel through an agricultural field, cutting the crop plants loose from the field, and gathering them. They also strip the crop portion (e.g. the grain) from the rest of the crop plant and discard the unwanted portion (also known as “material other than grain” or “MOG”).
Corn is harvested using an agricultural combine with a corn harvesting head or “corn head” attached on the front end thereof. The ears of corn are separated from the plant stalk itself, and are carried backwards into a threshing separating and cleaning system within the agricultural combine. In the combine the kernels of corn are separated from the corn cobs and are stored in a grain tank located in an upper portion of the agricultural combine.
The corn cobs and corn husks are then transmitted to a chopper disposed at the lower rear portion of the agricultural combine where they are chopped into small pieces, approximately 2 to 6 cm long, and are ejected from outlet of the chopper at the rear of the combine and spread over the ground.
In recent years, scientists have developed uses for corn cobs for such things as firing boilers or creating ethanol, plastics and other materials. It is desirable therefore to collect the corn cob pieces. It is not generally desirable to collect the husks. The technical problem, therefore, is providing some means for separating the corn cobs from the corn husks. Is also desirable to further direct the corn cob pieces to a storage location and to spread the husks over the ground.
US patent publication number 2009/0113867 describes a system for separating post-chopper MOG into lighter and heavier portions using an air blast. In this arrangement, the combine chopper empties into a conduit, which empties into a first blower 14. The first blower 14 accelerates the MOG (which is already traveling very fast as it exits the chopper) and sends it up a chute 16 which empties into a wagon as the agricultural combine travels through the field. A second blower 22 is provided to provide a cross flow of air across and through the flow path of MOG established by the chopper and the first blower. This cross flow of air is of sufficient speed to blow the lighter material (i.e. the corn husks) out of the MOG flow path and permit the heavier portion of the MOG (i.e. the chopped corn cobs) to continue onward through chute 16 into a collection vehicle 52. The lighter material ejected from the MOG flow is then spread over the ground, rather than collected in the vehicle 52
US patent publication number 2008/0248843 describes a system of dividing post-chopper MOG into two flow streams of variable proportions. The system includes a selectively steerable conduit 125 located between the combine chopper 118 and the blower 126 (described in US 2009/0113867) to separate a portion of the MOG that leaves the chopper and continues on to the blower. In this arrangement, the steerable conduit 125 has a flow dividing edge that is generally horizontal and moves up and down to mechanically direct the flow of material either into the blower 126 or downward toward the ground, depending upon the position to which it has moved.
In US 2009/0113867, the function of the air is to separate the flow of MOG based on its size, wind resistance, and density. When experiencing the air blast from the second blower 22, the denser materials, such as corn cobs, will continue through the conduit and into the vehicle 52. The lighter materials, such as corn husks, will be blown out of the conduit and directed over the ground.
In US 2008/0248843, the function of the conduit is to divide the flow of MOG into two streams. It does not separate the MOG flow into lighter or heavier portions.
Both of these arrangements suffer from a similar problem. Whether steered by a secondary air blast, or steered by movable conduit, the lighter material (i.e. the corn husks) is traveling so fast between the chopper and the blower that the blast of air is insufficient to steer it out of the vehicle entirely. Instead, the lighter material accumulates on the edge of the conduit that splits the flow, causing the corn husks to “hairpin” on the edge of the conduit and eventually plug the conduit.
Experimentation indicates that the problem is a function of the speed of the MOG flow traveling from the chopper through the first blower, and then up the chute and into the accompanying vehicle. At the high rates of speed the material travels from the chopper to the blower, there is a limited amount of time during which a cross flow air stream can separate the cobs from the husks. Given the limited amount of time for separation, the cross flow air separation arrangement of US 2009/113,867 A1, requires a substantial supply of high-speed air, and thus a powerful fan.
What is needed is a way to reduce the speed of the MOG, and while the speed is reduced, to separate the MOG into its lighter and heavier components using gravity as well as a secondary airflow.
It is an object of this invention to provide such a system.